Rice sheath blight(RSB)is a major destructive disease impeding rice production.Identifying key germplasm resources with increased resistance remains a challenge.However,the mechanisms underlying disease resistance are...Rice sheath blight(RSB)is a major destructive disease impeding rice production.Identifying key germplasm resources with increased resistance remains a challenge.However,the mechanisms underlying disease resistance are not yet fully understood.Cytochrome P450 monooxygenases(CYP450s)serve biosynthesis and metabolic detoxification functions in plants,but there is limited information about their role in the response induced by RSB.This study demonstrated that CYT02 belongs to the CYP73A100 subfamily and is a typical member of the CYP450s.Overexpression(OE)in rice of the cytochrome P450 monooxygenase cyt02 conferred increased resistance to RSB and increased vegetative tillering.Cyt02 may increase RSB resistance by regulating plant hormone synthesis,regulate reactive oxygen species(ROS)by coordinating the activity of antioxidant enzymes,and initiate phytoalexin synthesis in response to fungal infection.These research findings have laid a foundation for a deeper understanding of the function of cyt02 and offered a potential target gene for breeding rice varieties resistant to sheath blight.展开更多
Yellow rust(Puccinia striiformis f.sp.Tritici,YR)and fusarium head blight(Fusarium graminearum,FHB)are the two main diseases affecting wheat in the main grain-producing areas of East China,which is common for the two ...Yellow rust(Puccinia striiformis f.sp.Tritici,YR)and fusarium head blight(Fusarium graminearum,FHB)are the two main diseases affecting wheat in the main grain-producing areas of East China,which is common for the two diseases to appear simultaneously in some main production areas.It is necessary to discriminate wheat YR and FHB at the regional scale to accurately locate the disease in space,conduct detailed disease severity monitoring,and scientific control.Four images on different dates were acquired from Sentinel-2,Landsat-8,and Gaofen-1 during the critical period of winter wheat,and 22 remote sensing features that characterize the wheat growth status were then calculated.Meanwhile,6 meteorological parameters that reflect the wheat phenological information were also obtained by combining the site meteorological data and spatial interpolation technology.Then,the principal components(PCs)of comprehensive remote sensing and meteorological features were extracted with principal component analysis(PCA).The PCs-based discrimination models were established to map YR and FHB damage using the random forest(RF)and backpropagation neural network(BPNN).The models’performance was verified based on the disease field truth data(57 plots during the filling period)and 5-fold cross-validation.The results revealed that the PCs obtained after PCA dimensionality reduction outperformed the initial features(IFs)from remote sensing and meteorology in discriminating between the two diseases.Compared to the IFs,the average area under the curve for both micro-average and macro-average ROC curves increased by 0.07 in the PCs-based RF models and increased by 0.16 and 0.13,respectively,in the PCs-based BPNN models.Notably,the PCs-based BPNN discrimination model emerged as the most effective,achieving an overall accuracy of 83.9%.Our proposed discrimination model for wheat YR and FHB,coupled with multi-source remote sensing images and meteorological data,overcomes the limitations of a single-sensor and single-phase remote sensing information in multiple stress discrimination in cloudy and rainy areas.It performs well in revealing the damage spatial distribution of the two diseases at a regional scale,providing a basis for detailed disease severity monitoring,and scientific prevention and control.展开更多
Bacterial blight(BB),caused by Xanthomonas oryzae pathovar oryzae(Xoo),poses a significant threat to rice production,particularly in Asia and West Africa.Breeding resistance against BB in elite rice varieties is cruci...Bacterial blight(BB),caused by Xanthomonas oryzae pathovar oryzae(Xoo),poses a significant threat to rice production,particularly in Asia and West Africa.Breeding resistance against BB in elite rice varieties is crucial to advancing rice breeding program and supporting smallholder farmers.Transcription Activator-Like effectors(TALes)are key virulence factors in Xoo,with some targeting the susceptibility(S)genes such as the sugar transporter SWEET genes in rice.Among these,SWEET14 is an important S gene,with its promoter bound by the TALe TalC which exists across all sequenced African Xoo isolates.In the present study,we utilized CRISPR/Cas9-based cytidine and adenine base editors to alter the effector binding element(EBE)of TalC in the promoter of SWEET14 in rice cultivars Kitaake,IR24,and Zhonghua 11.Mutations with C to T changes in EBE led to reduced SWEET14 induction by TalC-containing Xoo strains,resulting in resistance to African Xoo isolates reliant on TalC for virulence.Conversely,A to G changes retained SWEET14 inducibility and susceptibility to Xoo in edited lines.Importantly,no off-target mutations were detected at predicted sites,and the edited lines exhibited no obvious defects in major agronomic traits in Kitaake.These results underscore the effectiveness of base editing systems for both molecular biology research and crop improvement endeavors.展开更多
Ethylene response factors(ERFs)are plant transcription agents that play a pivotal role in disease resistance through the ethylene signaling pathway.However,whether and how ERFs regulate resistance to sheath blight(ShB...Ethylene response factors(ERFs)are plant transcription agents that play a pivotal role in disease resistance through the ethylene signaling pathway.However,whether and how ERFs regulate resistance to sheath blight(ShB),caused by Rhizoctonia solani in rice,remains largely unknown.Here,we demonstrated that OsERF7 negatively regulates rice resistance to ShB by inhibiting phytoalexin biosynthesis.Overexpression of OsERF7(OsERF7OE)significantly decreased ShB resistance,whereas knockout of OsERF7(oserf7)enhanced it.Mechanistically,antioxidant enzyme activities are significantly reduced in OsERF7OE plants,but increased in oserf7 plants.Furthermore,transcriptome analysis revealed that oserf7 plants exhibited significant upregulation of pathogenesis-related(PR)and phytoalexin biosynthesis genes upon R.solani infection.Consistently,transcript levels of phytoalexin biosynthesis genes,including OsKSL7,OsKSL8,OsKOL5,and OsCPS4,were significantly elevated in oserf7 plants,but reduced in OsERF7OE plants in response to R.solani infection.Electrophoretic mobility shift assays and dual-luciferase(LUC)reporter assays further confirmed that OsERF7 directly binds to the promoters of OsKSL8,OsKOL5,and OsCPS4,thereby repressing their expression.In summary,our study revealed that OsERF7 negatively regulated rice resistance to ShB primarily by inhibiting phytoalexin biosynthesis.展开更多
Rice sheath blight is one of the serious rice diseases causing economic losses worldwide.Shenqinmycin,a broad-spectrum microbial metabolite pesticide,inhibits plant pathogens.This study investigated the sensitivity of...Rice sheath blight is one of the serious rice diseases causing economic losses worldwide.Shenqinmycin,a broad-spectrum microbial metabolite pesticide,inhibits plant pathogens.This study investigated the sensitivity of rice sheath blight pathogen to the biological pesticide by treating 45 strains isolated from three northeastern provinces with varying concentrations of Shenqinmycin.The effects on mycelial growth and sclerotial germination of the rice sheath blight pathogens were measured to determine the resistance levels.The results indicated that all tested strains were sensitive to Shenqinmycin,with EC50 values for Rhizoctonia solani ranging from 0.0487 mg·L^(-1) to 0.2348 mg·L^(-1),and a sensitivity baseline of 0.1292 mg·L^(-1).For Rhizoctonias oryzae-sativae,the EC50 values ranged from 0.0517 mg·L^(-1) to 0.1697 mg·L^(-1),with a sensitivity baseline of 0.1163 mg·L^(-1).Shenqinmycin had no effect on the sclerotial germination of either pathogen,suggesting its potential as an effective agent for controlling rice sheath blight.展开更多
In recent years,the prevalence of rice sheath blight caused by Rhizoctonia solani has significantly increased in Heilongjiang Province.Chemical control has become the primary control method.To cope with this,a novel m...In recent years,the prevalence of rice sheath blight caused by Rhizoctonia solani has significantly increased in Heilongjiang Province.Chemical control has become the primary control method.To cope with this,a novel mycelium growth rate method was employed to assess the toxicity of 13 fungicides,including a combination of 45%prochloraz and 125 g·mL^(-1)epoxiconazole,against R.solani.Additionally,the resistance of 99 R.solani strains to thifluzamide across various regions was also evaluated.The findings indicated that 75%trifloxystrobin-tebuconazole exhibited the most effective inhibitory effect,with an effective inhibitory medium concentration(EC50)value of 0.0101μg·mL^(-1).The EC50 values for 20%prothioconazole,125 g·mL^(-1)epoxiconazole,24%thifluzamide,and 50%hexaconazole were all less than 10μg·mL^(-1),indicating a better inhibitory effect on R.solani.The strongest synergistic effect was noted in the mixture of prochloraz and epoxiconazole at a 1:2 ratio,resulting in an EC50 value of 2.9917μg·mL^(-1),and a co-toxicity coefficient of 213.38.Among the 34 strains from Harbin City,the average EC50 value was 196.9341μg·mL^(-1)indicating the highest susceptiblility to thifluzamide.Conversely,15 strains from Shuangyashan City exhibited an average EC50 value of 364.7323μg·mL^(-1),reflecting the lowest sensitivity to thifluzamide.The sensitivity baseline EC50 value for R.solani was 253.8854μg·mL^(-1),with an overall resistance level between 0.1567 and 3.3292,indicating that the resistance level of R.solani in Heilongjiang Province remained low.Therefore,R.solani was still sensitive to thifluzamide in most areas of Heilongjiang Province,but there was a certain risk of resistance in Qitaihe City,which needed to be continuously monitored.At the same time,this study might provide a theoretical foundation for enhancing the prevention and management of the rice sheath blight.展开更多
Magnaporthe oryzae,the causal agent of rice blast,induces significant upregulation of OsPR10b,a pathogenesis-related(PR)pollen allergen(BetV-1)family gene.To investigate its role in immunity,we generated OsPR10b knock...Magnaporthe oryzae,the causal agent of rice blast,induces significant upregulation of OsPR10b,a pathogenesis-related(PR)pollen allergen(BetV-1)family gene.To investigate its role in immunity,we generated OsPR10b knockout mutants in the Zhonghua 11(ZH11)background.OsPR10b was predominantly expressed in rice calli and strongly induced by M.oryzae infection.Knockout mutants(ospr10b-1 and ospr10b-2)exhibited heightened susceptibility to both M.oryzae and Xanthomonas oryzae pv.oryzae(Xoo),demonstrating that OsPR10b positively regulates resistance to blast and bacterial blight.Our findings elucidate OsPR10b’s role in rice immunity and provide genetic resources for disease-resistant breeding.展开更多
Fusarium head blight(FHB),mainly caused by Fusarium graminearum,is one of the most devastating diseases of wheat worldwide.Identification and validation of major quantitative trait loci(QTLs)for FHB resistance without...Fusarium head blight(FHB),mainly caused by Fusarium graminearum,is one of the most devastating diseases of wheat worldwide.Identification and validation of major quantitative trait loci(QTLs)for FHB resistance without negative effects on agronomic traits is critical to success in breeding FHB-resistant cultivars.In this study,a stable major QTL on chromosome arm 2DL was identified by evaluating a recombinant inbred line(RIL)population derived from Shi4185×Shijiazhuang 8 in both field and greenhouse experiments.QTL mapping and pedigree analyses indicated that the 2DL QTL is the same as QFhb-2DL previously identified in Ji5265;therefore,it was designated Fhb9.Four kompetitive amplicon sequence polymorphism(KASP)markers were developed based on exome capture sequencing data to enhance marker density in the Fhb9 region,and it was delimited to an interval between single nucleotide polymorphism(SNP)markers KASP-12056(533.8 Mb)and KASP-525(525.9 Mb)explained 26.0-30.1%of the phenotypic variation.Analysis of the geographic distribution of the Fhb9 resistance allele suggests that it originated from the Huang-Huai winter wheat region in China.The very low frequency of Fhb9 in modern Chinese cultivars reveals that it has not been widely deployed in breeding programs.Field and greenhouse evaluations of yield-related traits in near-isogenic lines(NILs)contrasting in Fhb9 alleles reveal that the Fhb9 resistance allele have no adverse effects on these traits.Fhb9 showed an additive effect on enhancing FHB resistance with Fhb1.Therefore,Fhb9 is a valuable major QTL for improving FHB resistance in wheat,and the near-diagnostic markers developed in this study will facilitate its deployment in wheat breeding programs.展开更多
Fusarium head blight(FHB),mainly caused by Fusarium graminearum,is one of the most destructive fungal diseases affecting global wheat production.Elymus repens(2n=6×=42,StStStStHH),a wild relative of wheat,exhibit...Fusarium head blight(FHB),mainly caused by Fusarium graminearum,is one of the most destructive fungal diseases affecting global wheat production.Elymus repens(2n=6×=42,StStStStHH),a wild relative of wheat,exhibits numerous biotic and abiotic stress resistance characteristics.In previous studies,FHB resistance of E.repens has been transferred into common wheat through a wheat-E.repens partial amphidiploid and derivative lines.This study reports the development,characterization,and breeding utilization of K140-7,a novel wheat-E.repens translocation line conferring resistance to FHB.Genomic in situ hybridization(GISH)and fluorescence in situ hybridization(FISH)analyses demonstrated that K140-7 contained 40 common wheat chromosomes and two 7D·St translocation chromosomes.Subsequent characterization using oligonucleotide-FISH painting and single-gene FISH markers confirmed that the 7D fragment was a 7D short arm and the St fragment was a 7St long arm.Therefore,K140-7 was further identified as a 7DS·7StL translocation line with genetic compensation.Wheat 55K SNP array analysis of K140-7 demonstrated the 7DS·7StL translocation event.Field evaluations demonstrated that K140-7 exhibits agronomic performance comparable to its wheat parent.Based on St reference genome of Pseudoroegneria libanotica,21 simple sequence repeats(SSR)markers specific to 7StL were developed.Genetic analysis established that 7StL confers FHB resistance and carries the dominant FHB resistance locus,designated as QFhb.Er-7StL.Introgression of QFhb.Er-7StL into elite wheat cultivars has generated three second-generation 7DS·7StL translocation lines with enhanced agronomic traits.This study provides valuable novel germplasms and specific molecular markers for FHB resistance breeding in wheat.展开更多
Fusarium head blight(FHB)is a serious fungal disease that affect small grain cereals,causing significant wheat(Triticum aestivum L.)yield and quality losses globally.Breeding disease-resistant wheat varieties is key t...Fusarium head blight(FHB)is a serious fungal disease that affect small grain cereals,causing significant wheat(Triticum aestivum L.)yield and quality losses globally.Breeding disease-resistant wheat varieties is key to address FHB-related challenges,but its progress is delayed by traditional methods due to the small-scale,laborious and relatively subjective nature of manual assessment.This study presents a new approach that combines ultralow-altitude drone phenotyping with an optimized You Only Look Once(YOLO)model to examine FHB in wheat,enabling us to perform large-scale and automated symptomatic analysis of this disease.We first established an Open FHB(OFHB)training dataset,consisting of 4867 diseased and 106,801 healthy spikes collected from 132 commercial breeding lines during FHB progression.Then,a deep learning model called YOLOv8-WFD was trained for detecting healthy and diseased spikes,followed by an adaptive Excess Green method to identify symptomatic regions and thus FHBrelated traits on spikes.To study resistance levels,we employed an unsupervised SHapley Additive exPlanations(SHAP)method to pinpoint key traits between 10 and 20 d after inoculation(DAIs),resulting in the classification of 423 varieties trialed during the 2023–2024 growing seasons into four resistance levels(i.e.,highly and moderately susceptible,and moderately and highly resistant),which were highly correlated with field specialists’evaluations.Finally,we derived disease developmental curves based on measures of key traits during 10–20 DAI,quantifying varietal disease progression patterns over time.To our knowledge,this work represents a significant advancement in large-scale disease phenotyping and automated analysis of FHB in wheat,providing a valuable toolkit for breeders and plant researchers to assess resistance levels,select disease-resistant varieties,and understand dynamics of the fungal disease.展开更多
This study aimed to clarify the pathogen composition,biological characteristics,infection patterns,and effective control agents for panicle blight of rice in Heilongjiang Province.Diseased panicles were collected from...This study aimed to clarify the pathogen composition,biological characteristics,infection patterns,and effective control agents for panicle blight of rice in Heilongjiang Province.Diseased panicles were collected from different rice-growing areas in Heilongjiang Province and subjected to tissue isolation,pathogenicity tests,morphological observation,and molecular identification.The primary pathogens identified were Fusarium graminearum,Alternaria alternata and Nigrospora oryzae.The biological characteristics of these three pathogens were systematically investigated.Pathogenicity assays revealed that F.graminearum exhibited the strongest pathogenicity,followed by A.alternata,while N.oryzae was the weakest.In vitro toxicity tests screened highly effective fungicides:75%trifloxystrobin-tebuconazole showed the best inhibitory effect against F.graminearum(EC50=0.0140μg·mL^(-1));30%tebuconazole-azoxystrobin was the most effective against A.alternata(EC50=0.0060μg·mL^(-1))and N.oryzae(EC50=0.0310μg·mL^(-1)).展开更多
Sheath blight, caused by the Rhizoctonia solani Kuhn, is one of the most serious diseases of rice (Oryza sativa L.). The relationship between morphological traits and sheath blight resistance was investigated in 1999 ...Sheath blight, caused by the Rhizoctonia solani Kuhn, is one of the most serious diseases of rice (Oryza sativa L.). The relationship between morphological traits and sheath blight resistance was investigated in 1999 and 2000 by using a segregant population consisting of 240 inbred recombination lines, derived from an elite combination of Zhenshan 97 X Minghui 63. Partial correlation analysis between phenotypic data (morphological characteristics and heading date (HD)) and sheath blight ratings (SBR) showed that only one trait, plant compactness, was significantly correlated with resistance to sheath blight in both 1999 and 2000, eight traits, such as plant height, heading date, and penultimate leaf angle, were significantly correlated with SBR in either of the two years, and the remaining 10 morphological traits were not consistently associated with SBR in the two years. A major quantitative trait locus (QTL) controlling plant compactness was found to be in the site on chromosome 9 adjacent to the region responsible for qSB9, a major QTLs conferring sheath blight resistance. One out of the three QTLs contributing to a penultimate leaf angle was mapped approximately on the same region as another sheath blight resistance QTL, qSB5, located on chromosome 5. Whereas, no QTLs underlying most other traits was detected on the chromosomal region correlated with sheath blight resistance QTL. The results in the present study suggested that the morphological traits were not the main factors responsible for the SBR separation among the recombinant inbred lines (RILs) population. Nevertheless, some morphological characteristics had some indirect influence on expression of sheath blight resistance genes through altering a microclimate on paddy field so as to influence the infection of the pathogen and development of the disease. An efficient approach in resistance breeding to sheath blight was recommended by pyramiding major QTLs for sheath blight resistance and selecting those morphological traits that favor resistance gene expression.展开更多
[Objective] The aim was to study the effect of three new fungicides against rice sheath blight in field experiment. [Methods] The experiment set up 7 treatments with three times of repetition and designed by random gr...[Objective] The aim was to study the effect of three new fungicides against rice sheath blight in field experiment. [Methods] The experiment set up 7 treatments with three times of repetition and designed by random grouping. By using 5 sampling points in each plot, and investigating continuous 4 holes of each point, total plants, diseased plants and disease degrees were recorded. Then disease index and control efficiency were calculated, and variance analysis was carried out. [Results] 300 or 450 ml/hm^2 azoxystrobin ＋ difenoconazole 325 g/L SC had better control efficiency to rice sheath blight and had no phytotoxicity effect, we should use it at the initial disease stage and continuously spray 2-3 times. [Conclusion] The experiment provided a theoretical basis for controlling rice sheath blight using fungicides.展开更多
[ Objective] The paper was to evaluate the resistance of particular corn hybrids against northern leaf blight. [ Method ] Using artificial inoculation meth- od, the resistance of 238 copies of particular corn hybrids ...[ Objective] The paper was to evaluate the resistance of particular corn hybrids against northern leaf blight. [ Method ] Using artificial inoculation meth- od, the resistance of 238 copies of particular corn hybrids including silage corn, high oil corn, waxy corn and sweet corn against northern leaf blight was evaluated. [ Result] The corn samples with high resistance, resistance, moderate resistance, susceptibility and high susceptibility to northern leaf blight among 238 copies of materials in identification accounted for 0.8%, 20.6%, 44. 1%, 24.8% and 9.7%, respectively. Different types of varieties had significant difference in resist- ance. Among cern varieties with moderate resistance or higher level, silage corn accounted for 87.8% ; high oil corn and waxy corn accounted for 73.3% and 61.3 %, respectively; sweet corn was less, accounting for 44.2%. Sixteen of 30 approved particular corn varieties showed resistance, accounting for 53.3 % of total approved varieties. [Condusion] The paper provided theoretical basis for breeding and planting of particular corn hybrids with resistance against northern leaf blight.展开更多
[ Objective] The paper was to study the cultural characteristic of the pathogen of Rice Sheath Blight （ Rhizoctonia solani Kuhn） and its pathogenicity in Sichuan regions. [ Method] The samples of rice sheath blight ...[ Objective] The paper was to study the cultural characteristic of the pathogen of Rice Sheath Blight （ Rhizoctonia solani Kuhn） and its pathogenicity in Sichuan regions. [ Method] The samples of rice sheath blight collected from six main rice planting areas in Sichuan regions were separated. The separated pathogen of rice sheath blight was cultured on PDA medium, and its cultural characteristic was recorded. Meanwhile, the pathogenicity of the obtained 23 strains was determined. [ Result] The growth rates among different strains had significant difference. According to the growth rate, only one strain belonged to medium strain（colony diameter： 40 mm≤（Ф≤60 mm）, the rest were all slow-type strains （colony diam- eter Ф〈40 mm）, and there was no strain with fast growth rate （colony diameter Ф 〉 60 mm）. Pathogenicity test showed that the pathogenicity among strains was significantly different, only one strain had strong pathogenicity, and the others all had moderate or weak pathogenicity. [ Conclu- sion] The study confirmed the basic biological characteristics of the pathogen of rice sheath blight in Sichuan region, which would provide theoretical basis for effective control of rice sheath blight in the region.展开更多
[ Objective ] The paper was to explore the combined application technique of organic fertilizer and two biocontrol agents against pepper blight in green- house hot pepper in Qinghai Province. [Method] By L4 （23）orth...[ Objective ] The paper was to explore the combined application technique of organic fertilizer and two biocontrol agents against pepper blight in green- house hot pepper in Qinghai Province. [Method] By L4 （23）orthogonal design, the effects of combined application of two biocontrol agents against pepper blight and organic fertilizer on control effects against pepper blight and the yield of hot pepper were studied in greenhouse hot pepper base in Ledu County of Qinghai Province. [ Result] The effects of various factors affecting the relative control effect against pepper blight in sequence were biecontrol agent A5 〉 biecontrol agent B2 〉 organic fertilizer, and the optimal combination was organic fertilizer 1 800 kg/hm^2, agent B2 30 kg/hm^2 and agent A5 45 kg/hm^2. The effects on hot pepper yield in sequence were organic fertilizer 〉 biocontrol agent B2 〉 biocontrol agent AS, and the optimal combination was organic fertilizer 900 kg/hm^2 , agent 132 15 kg/hm^2, agent A5 22.5 kg/hm2. [ Conclusion] Combined with control effect of pepper blight and yield benefit, the application technique of biocontrol agents pro- moted in local hot pepper production could be confirmed as follows ： agent A5 45 kg/hm^2, agent B2 15 kg/hm^2, organic fertilizer 900 kg/hm^2 ; the field control effect at this moment could reach 76.31%, the yield could reach 35 573 kg/hm^2 , and the newly increased output value could be 13 029 yuan/hm^2 with input and output ratio of 1： 7.9.展开更多
In this study, a population of 119 chromosome segment substitution lines （CSSLs） derived from backcross between indica 9311 and japonica Nipponbare was employed to map quantitative trait loci （QTL） associated with...In this study, a population of 119 chromosome segment substitution lines （CSSLs） derived from backcross between indica 9311 and japonica Nipponbare was employed to map quantitative trait loci （QTL） associated with sheath blight resis-tance in rice with toothpick inoculation method. A total of three sheath blight resis-tance-associated QTLs （qsb8-1, qsb8-2 and qsb8-3） were identified, which were lo-cated on adjacent molecular markers RM3262, RM5485 and RM3496 of chromo-some 8; the genetic interval was 81.7cM-91.7cM, 91.7cM-108.1cM and 108.1cM-119.6cM, respectively. The additive effect of qsb8-2 was negative, indicating that sheath blight resistance of susceptible parent harboring qsb8-2 fragment was en-hanced; additive effects of qsb8-1 and qsb8-3 were positive, indicating that sheath blight resistance of susceptible parent harboring qsb8-1 and qsb8-3 fragments was reduced.展开更多
基金supported by the Sichuan Province International Science and Technology Innovation Cooperation(2024YFHZ0299)the Project of Science and Technology Department of Sichuan Province(2022YFH0031)Chengdu Science and Technology Bureau(2024-YF05-02168-SN).
文摘Rice sheath blight(RSB)is a major destructive disease impeding rice production.Identifying key germplasm resources with increased resistance remains a challenge.However,the mechanisms underlying disease resistance are not yet fully understood.Cytochrome P450 monooxygenases(CYP450s)serve biosynthesis and metabolic detoxification functions in plants,but there is limited information about their role in the response induced by RSB.This study demonstrated that CYT02 belongs to the CYP73A100 subfamily and is a typical member of the CYP450s.Overexpression(OE)in rice of the cytochrome P450 monooxygenase cyt02 conferred increased resistance to RSB and increased vegetative tillering.Cyt02 may increase RSB resistance by regulating plant hormone synthesis,regulate reactive oxygen species(ROS)by coordinating the activity of antioxidant enzymes,and initiate phytoalexin synthesis in response to fungal infection.These research findings have laid a foundation for a deeper understanding of the function of cyt02 and offered a potential target gene for breeding rice varieties resistant to sheath blight.
基金supported by National Key R&D Program of China(2022YFD2000100)National Natural Science Foundation of China(42401400)Zhejiang Provincial Key Research and Development Program(2023C02018).
文摘Yellow rust(Puccinia striiformis f.sp.Tritici,YR)and fusarium head blight(Fusarium graminearum,FHB)are the two main diseases affecting wheat in the main grain-producing areas of East China,which is common for the two diseases to appear simultaneously in some main production areas.It is necessary to discriminate wheat YR and FHB at the regional scale to accurately locate the disease in space,conduct detailed disease severity monitoring,and scientific control.Four images on different dates were acquired from Sentinel-2,Landsat-8,and Gaofen-1 during the critical period of winter wheat,and 22 remote sensing features that characterize the wheat growth status were then calculated.Meanwhile,6 meteorological parameters that reflect the wheat phenological information were also obtained by combining the site meteorological data and spatial interpolation technology.Then,the principal components(PCs)of comprehensive remote sensing and meteorological features were extracted with principal component analysis(PCA).The PCs-based discrimination models were established to map YR and FHB damage using the random forest(RF)and backpropagation neural network(BPNN).The models’performance was verified based on the disease field truth data(57 plots during the filling period)and 5-fold cross-validation.The results revealed that the PCs obtained after PCA dimensionality reduction outperformed the initial features(IFs)from remote sensing and meteorology in discriminating between the two diseases.Compared to the IFs,the average area under the curve for both micro-average and macro-average ROC curves increased by 0.07 in the PCs-based RF models and increased by 0.16 and 0.13,respectively,in the PCs-based BPNN models.Notably,the PCs-based BPNN discrimination model emerged as the most effective,achieving an overall accuracy of 83.9%.Our proposed discrimination model for wheat YR and FHB,coupled with multi-source remote sensing images and meteorological data,overcomes the limitations of a single-sensor and single-phase remote sensing information in multiple stress discrimination in cloudy and rainy areas.It performs well in revealing the damage spatial distribution of the two diseases at a regional scale,providing a basis for detailed disease severity monitoring,and scientific prevention and control.
基金supported by a sub-award to the University of Missouri from the Heinrich Heine University of Dusseldorf funded by the Bill&Melinda Gates Foundation(OPP1155704)(Bing Yang)and the China Scholar Council(Chenhao Li,as a joint Ph.D.student).
文摘Bacterial blight(BB),caused by Xanthomonas oryzae pathovar oryzae(Xoo),poses a significant threat to rice production,particularly in Asia and West Africa.Breeding resistance against BB in elite rice varieties is crucial to advancing rice breeding program and supporting smallholder farmers.Transcription Activator-Like effectors(TALes)are key virulence factors in Xoo,with some targeting the susceptibility(S)genes such as the sugar transporter SWEET genes in rice.Among these,SWEET14 is an important S gene,with its promoter bound by the TALe TalC which exists across all sequenced African Xoo isolates.In the present study,we utilized CRISPR/Cas9-based cytidine and adenine base editors to alter the effector binding element(EBE)of TalC in the promoter of SWEET14 in rice cultivars Kitaake,IR24,and Zhonghua 11.Mutations with C to T changes in EBE led to reduced SWEET14 induction by TalC-containing Xoo strains,resulting in resistance to African Xoo isolates reliant on TalC for virulence.Conversely,A to G changes retained SWEET14 inducibility and susceptibility to Xoo in edited lines.Importantly,no off-target mutations were detected at predicted sites,and the edited lines exhibited no obvious defects in major agronomic traits in Kitaake.These results underscore the effectiveness of base editing systems for both molecular biology research and crop improvement endeavors.
基金supported by the National Natural Science Foundation of China(Grant Nos.32200430 and 32272110)Jiangsu Province Higher Vocational College Teacher Professional Leader High-End Training Program,China(Grant No.2023GRFX083)+2 种基金China Postdoctoral Science Foundation(Grant No.2022M712700)Jiangsu Funding Program for Excellent Postdoctoral Talent,China(Grant No.2022ZB628)a Project Funded by Priority Academic Program Development of Jiangsu Higher Education Institutions,China.
文摘Ethylene response factors(ERFs)are plant transcription agents that play a pivotal role in disease resistance through the ethylene signaling pathway.However,whether and how ERFs regulate resistance to sheath blight(ShB),caused by Rhizoctonia solani in rice,remains largely unknown.Here,we demonstrated that OsERF7 negatively regulates rice resistance to ShB by inhibiting phytoalexin biosynthesis.Overexpression of OsERF7(OsERF7OE)significantly decreased ShB resistance,whereas knockout of OsERF7(oserf7)enhanced it.Mechanistically,antioxidant enzyme activities are significantly reduced in OsERF7OE plants,but increased in oserf7 plants.Furthermore,transcriptome analysis revealed that oserf7 plants exhibited significant upregulation of pathogenesis-related(PR)and phytoalexin biosynthesis genes upon R.solani infection.Consistently,transcript levels of phytoalexin biosynthesis genes,including OsKSL7,OsKSL8,OsKOL5,and OsCPS4,were significantly elevated in oserf7 plants,but reduced in OsERF7OE plants in response to R.solani infection.Electrophoretic mobility shift assays and dual-luciferase(LUC)reporter assays further confirmed that OsERF7 directly binds to the promoters of OsKSL8,OsKOL5,and OsCPS4,thereby repressing their expression.In summary,our study revealed that OsERF7 negatively regulated rice resistance to ShB primarily by inhibiting phytoalexin biosynthesis.
基金Supported by the Green Plant Protection Project(213010801)the Heilongjiang Provincial Key R&D Program Projects(20232X02B0502)。
文摘Rice sheath blight is one of the serious rice diseases causing economic losses worldwide.Shenqinmycin,a broad-spectrum microbial metabolite pesticide,inhibits plant pathogens.This study investigated the sensitivity of rice sheath blight pathogen to the biological pesticide by treating 45 strains isolated from three northeastern provinces with varying concentrations of Shenqinmycin.The effects on mycelial growth and sclerotial germination of the rice sheath blight pathogens were measured to determine the resistance levels.The results indicated that all tested strains were sensitive to Shenqinmycin,with EC50 values for Rhizoctonia solani ranging from 0.0487 mg·L^(-1) to 0.2348 mg·L^(-1),and a sensitivity baseline of 0.1292 mg·L^(-1).For Rhizoctonias oryzae-sativae,the EC50 values ranged from 0.0517 mg·L^(-1) to 0.1697 mg·L^(-1),with a sensitivity baseline of 0.1163 mg·L^(-1).Shenqinmycin had no effect on the sclerotial germination of either pathogen,suggesting its potential as an effective agent for controlling rice sheath blight.
基金Supported by the Green Plant Protection Project(213010801)the Heilongjiang Province Key Research and Development Plan Project(20232X02 B0502)the Natural Science Foundation of Heilongjiang Province(LH2022C022)。
文摘In recent years,the prevalence of rice sheath blight caused by Rhizoctonia solani has significantly increased in Heilongjiang Province.Chemical control has become the primary control method.To cope with this,a novel mycelium growth rate method was employed to assess the toxicity of 13 fungicides,including a combination of 45%prochloraz and 125 g·mL^(-1)epoxiconazole,against R.solani.Additionally,the resistance of 99 R.solani strains to thifluzamide across various regions was also evaluated.The findings indicated that 75%trifloxystrobin-tebuconazole exhibited the most effective inhibitory effect,with an effective inhibitory medium concentration(EC50)value of 0.0101μg·mL^(-1).The EC50 values for 20%prothioconazole,125 g·mL^(-1)epoxiconazole,24%thifluzamide,and 50%hexaconazole were all less than 10μg·mL^(-1),indicating a better inhibitory effect on R.solani.The strongest synergistic effect was noted in the mixture of prochloraz and epoxiconazole at a 1:2 ratio,resulting in an EC50 value of 2.9917μg·mL^(-1),and a co-toxicity coefficient of 213.38.Among the 34 strains from Harbin City,the average EC50 value was 196.9341μg·mL^(-1)indicating the highest susceptiblility to thifluzamide.Conversely,15 strains from Shuangyashan City exhibited an average EC50 value of 364.7323μg·mL^(-1),reflecting the lowest sensitivity to thifluzamide.The sensitivity baseline EC50 value for R.solani was 253.8854μg·mL^(-1),with an overall resistance level between 0.1567 and 3.3292,indicating that the resistance level of R.solani in Heilongjiang Province remained low.Therefore,R.solani was still sensitive to thifluzamide in most areas of Heilongjiang Province,but there was a certain risk of resistance in Qitaihe City,which needed to be continuously monitored.At the same time,this study might provide a theoretical foundation for enhancing the prevention and management of the rice sheath blight.
基金supported by the Special Fund for Agro-scientific Research in the Public Interest of Fujian Province,China(Grant No.2023R1021006)the National Natural Science Foundation of China(Grant No.32402387)+1 种基金the extended research project of the National Natural Science Foundation of China(Grant No.GJYS202511)the 5511 Collaborative Engineering Project,China(Grant No.XTCXGC2021001).
文摘Magnaporthe oryzae,the causal agent of rice blast,induces significant upregulation of OsPR10b,a pathogenesis-related(PR)pollen allergen(BetV-1)family gene.To investigate its role in immunity,we generated OsPR10b knockout mutants in the Zhonghua 11(ZH11)background.OsPR10b was predominantly expressed in rice calli and strongly induced by M.oryzae infection.Knockout mutants(ospr10b-1 and ospr10b-2)exhibited heightened susceptibility to both M.oryzae and Xanthomonas oryzae pv.oryzae(Xoo),demonstrating that OsPR10b positively regulates resistance to blast and bacterial blight.Our findings elucidate OsPR10b’s role in rice immunity and provide genetic resources for disease-resistant breeding.
基金supported by the National Key Research and Development Program of China(2022YFD1201502)partially funded by the Talent Funds of China Agricultural University(2021RC009)the US Wheat and Barley Scab Initiative.
文摘Fusarium head blight(FHB),mainly caused by Fusarium graminearum,is one of the most devastating diseases of wheat worldwide.Identification and validation of major quantitative trait loci(QTLs)for FHB resistance without negative effects on agronomic traits is critical to success in breeding FHB-resistant cultivars.In this study,a stable major QTL on chromosome arm 2DL was identified by evaluating a recombinant inbred line(RIL)population derived from Shi4185×Shijiazhuang 8 in both field and greenhouse experiments.QTL mapping and pedigree analyses indicated that the 2DL QTL is the same as QFhb-2DL previously identified in Ji5265;therefore,it was designated Fhb9.Four kompetitive amplicon sequence polymorphism(KASP)markers were developed based on exome capture sequencing data to enhance marker density in the Fhb9 region,and it was delimited to an interval between single nucleotide polymorphism(SNP)markers KASP-12056(533.8 Mb)and KASP-525(525.9 Mb)explained 26.0-30.1%of the phenotypic variation.Analysis of the geographic distribution of the Fhb9 resistance allele suggests that it originated from the Huang-Huai winter wheat region in China.The very low frequency of Fhb9 in modern Chinese cultivars reveals that it has not been widely deployed in breeding programs.Field and greenhouse evaluations of yield-related traits in near-isogenic lines(NILs)contrasting in Fhb9 alleles reveal that the Fhb9 resistance allele have no adverse effects on these traits.Fhb9 showed an additive effect on enhancing FHB resistance with Fhb1.Therefore,Fhb9 is a valuable major QTL for improving FHB resistance in wheat,and the near-diagnostic markers developed in this study will facilitate its deployment in wheat breeding programs.
基金supported by the National Natural Science Foundation of China(31971883 and 32200180)the Major Program of National Agricultural Science and Technology of China(NK20220607)+2 种基金the Special Projects of the Central Government in Guidance of Local Science and Technology Development,China(2023ZYD0088)the Science and Technology Bureau of Sichuan Province,China(2021YFYZ0002,2022ZDZX0014,2023NSFSC1995,and 2022YFSY0035)the Science and Technology Bureau of Chengdu City,China(2022-YF05-00449-SN).
文摘Fusarium head blight(FHB),mainly caused by Fusarium graminearum,is one of the most destructive fungal diseases affecting global wheat production.Elymus repens(2n=6×=42,StStStStHH),a wild relative of wheat,exhibits numerous biotic and abiotic stress resistance characteristics.In previous studies,FHB resistance of E.repens has been transferred into common wheat through a wheat-E.repens partial amphidiploid and derivative lines.This study reports the development,characterization,and breeding utilization of K140-7,a novel wheat-E.repens translocation line conferring resistance to FHB.Genomic in situ hybridization(GISH)and fluorescence in situ hybridization(FISH)analyses demonstrated that K140-7 contained 40 common wheat chromosomes and two 7D·St translocation chromosomes.Subsequent characterization using oligonucleotide-FISH painting and single-gene FISH markers confirmed that the 7D fragment was a 7D short arm and the St fragment was a 7St long arm.Therefore,K140-7 was further identified as a 7DS·7StL translocation line with genetic compensation.Wheat 55K SNP array analysis of K140-7 demonstrated the 7DS·7StL translocation event.Field evaluations demonstrated that K140-7 exhibits agronomic performance comparable to its wheat parent.Based on St reference genome of Pseudoroegneria libanotica,21 simple sequence repeats(SSR)markers specific to 7StL were developed.Genetic analysis established that 7StL confers FHB resistance and carries the dominant FHB resistance locus,designated as QFhb.Er-7StL.Introgression of QFhb.Er-7StL into elite wheat cultivars has generated three second-generation 7DS·7StL translocation lines with enhanced agronomic traits.This study provides valuable novel germplasms and specific molecular markers for FHB resistance breeding in wheat.
基金supported by the Biological Breeding-National Science and Technology Major Project(2023ZD04025 to Xiu’e Wang)the Seed Industry Revitalization Project of Jiangsu Province(JBGS(2021)006 to Xiu’e Wang)+3 种基金the National Natural Science Foundation of China(32070400 to Ji Zhou)Ji Zhou,Robert Jackson,and Greg Deakin were partially supported by the Allan&Gill Gray Foundation’Sustainable Productivity for Crop Improvement(G118688 to the University of Cambridge and Q-20-0370 to NIAB)Ji Zhou was supported by the United Kingdom Research and Innovation’s(UKRI)Biotechnology and Bio logical Sciences Research Council(BBSRC)AI in Bioscience Grant(BB/Y513969/1 to Ji Zhou)The UK-China research activities were supported by the BBSRC’s International Partnership Grant(BB/Y514081/1 to NIAB)
文摘Fusarium head blight(FHB)is a serious fungal disease that affect small grain cereals,causing significant wheat(Triticum aestivum L.)yield and quality losses globally.Breeding disease-resistant wheat varieties is key to address FHB-related challenges,but its progress is delayed by traditional methods due to the small-scale,laborious and relatively subjective nature of manual assessment.This study presents a new approach that combines ultralow-altitude drone phenotyping with an optimized You Only Look Once(YOLO)model to examine FHB in wheat,enabling us to perform large-scale and automated symptomatic analysis of this disease.We first established an Open FHB(OFHB)training dataset,consisting of 4867 diseased and 106,801 healthy spikes collected from 132 commercial breeding lines during FHB progression.Then,a deep learning model called YOLOv8-WFD was trained for detecting healthy and diseased spikes,followed by an adaptive Excess Green method to identify symptomatic regions and thus FHBrelated traits on spikes.To study resistance levels,we employed an unsupervised SHapley Additive exPlanations(SHAP)method to pinpoint key traits between 10 and 20 d after inoculation(DAIs),resulting in the classification of 423 varieties trialed during the 2023–2024 growing seasons into four resistance levels(i.e.,highly and moderately susceptible,and moderately and highly resistant),which were highly correlated with field specialists’evaluations.Finally,we derived disease developmental curves based on measures of key traits during 10–20 DAI,quantifying varietal disease progression patterns over time.To our knowledge,this work represents a significant advancement in large-scale disease phenotyping and automated analysis of FHB in wheat,providing a valuable toolkit for breeders and plant researchers to assess resistance levels,select disease-resistant varieties,and understand dynamics of the fungal disease.
基金Supported by the Green Plant Protection Project in Heilongjiang Province(2130108)the Key R&D Program Project of Heilongjiang Province(2023ZX02B0502)the Heilongjiang Province Rice Modern Agriculture Industry Technology Collaborative Innovation System Project(2025)。
文摘This study aimed to clarify the pathogen composition,biological characteristics,infection patterns,and effective control agents for panicle blight of rice in Heilongjiang Province.Diseased panicles were collected from different rice-growing areas in Heilongjiang Province and subjected to tissue isolation,pathogenicity tests,morphological observation,and molecular identification.The primary pathogens identified were Fusarium graminearum,Alternaria alternata and Nigrospora oryzae.The biological characteristics of these three pathogens were systematically investigated.Pathogenicity assays revealed that F.graminearum exhibited the strongest pathogenicity,followed by A.alternata,while N.oryzae was the weakest.In vitro toxicity tests screened highly effective fungicides:75%trifloxystrobin-tebuconazole showed the best inhibitory effect against F.graminearum(EC50=0.0140μg·mL^(-1));30%tebuconazole-azoxystrobin was the most effective against A.alternata(EC50=0.0060μg·mL^(-1))and N.oryzae(EC50=0.0310μg·mL^(-1)).
文摘Sheath blight, caused by the Rhizoctonia solani Kuhn, is one of the most serious diseases of rice (Oryza sativa L.). The relationship between morphological traits and sheath blight resistance was investigated in 1999 and 2000 by using a segregant population consisting of 240 inbred recombination lines, derived from an elite combination of Zhenshan 97 X Minghui 63. Partial correlation analysis between phenotypic data (morphological characteristics and heading date (HD)) and sheath blight ratings (SBR) showed that only one trait, plant compactness, was significantly correlated with resistance to sheath blight in both 1999 and 2000, eight traits, such as plant height, heading date, and penultimate leaf angle, were significantly correlated with SBR in either of the two years, and the remaining 10 morphological traits were not consistently associated with SBR in the two years. A major quantitative trait locus (QTL) controlling plant compactness was found to be in the site on chromosome 9 adjacent to the region responsible for qSB9, a major QTLs conferring sheath blight resistance. One out of the three QTLs contributing to a penultimate leaf angle was mapped approximately on the same region as another sheath blight resistance QTL, qSB5, located on chromosome 5. Whereas, no QTLs underlying most other traits was detected on the chromosomal region correlated with sheath blight resistance QTL. The results in the present study suggested that the morphological traits were not the main factors responsible for the SBR separation among the recombinant inbred lines (RILs) population. Nevertheless, some morphological characteristics had some indirect influence on expression of sheath blight resistance genes through altering a microclimate on paddy field so as to influence the infection of the pathogen and development of the disease. An efficient approach in resistance breeding to sheath blight was recommended by pyramiding major QTLs for sheath blight resistance and selecting those morphological traits that favor resistance gene expression.
文摘[Objective] The aim was to study the effect of three new fungicides against rice sheath blight in field experiment. [Methods] The experiment set up 7 treatments with three times of repetition and designed by random grouping. By using 5 sampling points in each plot, and investigating continuous 4 holes of each point, total plants, diseased plants and disease degrees were recorded. Then disease index and control efficiency were calculated, and variance analysis was carried out. [Results] 300 or 450 ml/hm^2 azoxystrobin ＋ difenoconazole 325 g/L SC had better control efficiency to rice sheath blight and had no phytotoxicity effect, we should use it at the initial disease stage and continuously spray 2-3 times. [Conclusion] The experiment provided a theoretical basis for controlling rice sheath blight using fungicides.
基金Supported by Shanxi Scientific Research Project ( 20090311002-3)Science and Technology Research Project of Shanxi Academy of Agricultural Sciences( YGG0927)~~
文摘[ Objective] The paper was to evaluate the resistance of particular corn hybrids against northern leaf blight. [ Method ] Using artificial inoculation meth- od, the resistance of 238 copies of particular corn hybrids including silage corn, high oil corn, waxy corn and sweet corn against northern leaf blight was evaluated. [ Result] The corn samples with high resistance, resistance, moderate resistance, susceptibility and high susceptibility to northern leaf blight among 238 copies of materials in identification accounted for 0.8%, 20.6%, 44. 1%, 24.8% and 9.7%, respectively. Different types of varieties had significant difference in resist- ance. Among cern varieties with moderate resistance or higher level, silage corn accounted for 87.8% ; high oil corn and waxy corn accounted for 73.3% and 61.3 %, respectively; sweet corn was less, accounting for 44.2%. Sixteen of 30 approved particular corn varieties showed resistance, accounting for 53.3 % of total approved varieties. [Condusion] The paper provided theoretical basis for breeding and planting of particular corn hybrids with resistance against northern leaf blight.
基金Supported by Public Service Sector (Agriculture) Projects (nyhyzx07-049)~~
文摘[ Objective] The paper was to study the cultural characteristic of the pathogen of Rice Sheath Blight （ Rhizoctonia solani Kuhn） and its pathogenicity in Sichuan regions. [ Method] The samples of rice sheath blight collected from six main rice planting areas in Sichuan regions were separated. The separated pathogen of rice sheath blight was cultured on PDA medium, and its cultural characteristic was recorded. Meanwhile, the pathogenicity of the obtained 23 strains was determined. [ Result] The growth rates among different strains had significant difference. According to the growth rate, only one strain belonged to medium strain（colony diameter： 40 mm≤（Ф≤60 mm）, the rest were all slow-type strains （colony diam- eter Ф〈40 mm）, and there was no strain with fast growth rate （colony diameter Ф 〉 60 mm）. Pathogenicity test showed that the pathogenicity among strains was significantly different, only one strain had strong pathogenicity, and the others all had moderate or weak pathogenicity. [ Conclu- sion] The study confirmed the basic biological characteristics of the pathogen of rice sheath blight in Sichuan region, which would provide theoretical basis for effective control of rice sheath blight in the region.
文摘[ Objective ] The paper was to explore the combined application technique of organic fertilizer and two biocontrol agents against pepper blight in green- house hot pepper in Qinghai Province. [Method] By L4 （23）orthogonal design, the effects of combined application of two biocontrol agents against pepper blight and organic fertilizer on control effects against pepper blight and the yield of hot pepper were studied in greenhouse hot pepper base in Ledu County of Qinghai Province. [ Result] The effects of various factors affecting the relative control effect against pepper blight in sequence were biecontrol agent A5 〉 biecontrol agent B2 〉 organic fertilizer, and the optimal combination was organic fertilizer 1 800 kg/hm^2, agent B2 30 kg/hm^2 and agent A5 45 kg/hm^2. The effects on hot pepper yield in sequence were organic fertilizer 〉 biocontrol agent B2 〉 biocontrol agent AS, and the optimal combination was organic fertilizer 900 kg/hm^2 , agent 132 15 kg/hm^2, agent A5 22.5 kg/hm2. [ Conclusion] Combined with control effect of pepper blight and yield benefit, the application technique of biocontrol agents pro- moted in local hot pepper production could be confirmed as follows ： agent A5 45 kg/hm^2, agent B2 15 kg/hm^2, organic fertilizer 900 kg/hm^2 ; the field control effect at this moment could reach 76.31%, the yield could reach 35 573 kg/hm^2 , and the newly increased output value could be 13 029 yuan/hm^2 with input and output ratio of 1： 7.9.
基金Supported by Specific Fund for the Independent Innovation of Agricultural Science and Technology[CX(11)1020]~~
文摘In this study, a population of 119 chromosome segment substitution lines （CSSLs） derived from backcross between indica 9311 and japonica Nipponbare was employed to map quantitative trait loci （QTL） associated with sheath blight resis-tance in rice with toothpick inoculation method. A total of three sheath blight resis-tance-associated QTLs （qsb8-1, qsb8-2 and qsb8-3） were identified, which were lo-cated on adjacent molecular markers RM3262, RM5485 and RM3496 of chromo-some 8; the genetic interval was 81.7cM-91.7cM, 91.7cM-108.1cM and 108.1cM-119.6cM, respectively. The additive effect of qsb8-2 was negative, indicating that sheath blight resistance of susceptible parent harboring qsb8-2 fragment was en-hanced; additive effects of qsb8-1 and qsb8-3 were positive, indicating that sheath blight resistance of susceptible parent harboring qsb8-1 and qsb8-3 fragments was reduced.
